Knife sharpener



y 1953 G. H. HOLZHAUSEN ET AL 2,841,931

KNIFE SHARPENER Filed May 31, 1957 GLEN H. HOLZHAUSEN WILLIAM W.HAEFLIGER INVENTOR. M44 44 MW BY United States Patent KNIFE SHARPENERGlen H. Holzhausen, Palos Verdes, and William W. Haefliger, Pasadena,Calif.

Application May 31, 1957, Serial No. 662,943

8 Claims. (Cl. 51-241) This invention relates to sharpening devices, andmore particularly to knife sharpening devices which may be attached toand driven by electrical appliances of the home electric mixer type.

This application is a continuation-in-part of application, Serial No.347,246, filed April 7, 1953, now abandoned.

It is an object of the invention to provide a novel sharpening deviceincorporating means for coupling the sharpening device in operativeengagement with a variable speed home electric mixer, so that anabrasive element carried by the sharpening device may be rotated at itsmost efllcient sharpening speed with the spin axis of the rotatingabrasive element disposed vertically, so that a knife blade may besharpened by moving it horizontally into engagement with the abrasiveelement on opposite sides of the shaft.

It is another object of the invention to provide a sharpening devicehaving a novel rotatable housing with engagement means attached theretofor limiting rotation of the housing, so that a knife blade may beguided by the housing into engagement with a rotating abrasive elementenclosed by the housing.

\ It is a further object of the invention to provide a novel knifesharpening device including separate rotatable housing membersprotecting and enclosing a rotating abrasive element, the housingmembers being spaced apart to provide an annular groove for theinsertion of a knife blade to be sharpened against the abrasive element.

Other objects and advantages will become apparent from a considerationof the following description and the appended claims in conjunction withthe accompanying drawings wherein:

Figure 1 is a sectional view of one form of sharpening device of thepresent invention;

Figure 2 is a plan view of the end of the shaft illustrated in Fig. 1,and taken along line 2-2 thereof;

Figure 3 is an elevational view of the sharpening device illustrated inFig. l, and taken along line 33 thereof;

Figure 4 is a sectional view of another form of the sharpening device ofthe present invention;

Figure 5 is a sectional view of another form of the sharpening device ofthe present invention; and

Figure 6 is a sectional view of still another form of the sharpeningdevice.

Referring now to Fig. 1, there is therein illustrated one form of thenovel sharpening unit. The knife sharpener includes an elongatedcircular shaft 11 which carries an abrasive means such as a wheel ordisc 12 mounted thereon. The abrasive wheel is centrally apertured toaccommodate the portion 13 of the shaft, and washers 14 and 15 arepositioned on either side of the abrasive wheel. The lower end portionof the shaft is threaded, and a nut 16 is tightened against washer 15,forcing the abrasive wheel and washer 14 upwardly so that washer 14engages shoulder 17 of the stepped portion 18 of the shaft, with theresult that the washers and abrasive wheel are rigidly and frictionallygripped between the nut and 2,841,931 Patented July 8,1958

the stepped portion of the shaft. At the same time, the upper surface 19and lower surf-ace 20 of the abrasive wheel are aligned by the washers14 and in planes which lie perpendicular to the axis of the shaft. Theabrasive disc itself is comprised of an abrasive material dispersedthroughout a binder, such as is commonly used in grinding wheels used ingrinding metallic objects. The abrasive wheel includes an annularbeveled portion 21 which slopes upwardly and outwardly from the lowersurface of the wheel at a small angle to intersect the cylindrical outersurface 22 of the wheel.

A housing 25 enclosing a portion of the abrasive element is rotatablymounted about the shaft 11 by means of a cylindrical bearing 26 which iscarried by the stepped portion 18 of the shaft. The bearing may consistof bronze or oilite, or any suitable bearing material. A cylindricalportion 27 of the housing is pressed on the outer surface of the bearingso as to be rigidly mounted thereon to support the remaining portion ofthe housing 25. Housing 25 includes a wall portion 28 extendingoutwardly from the shaft above the upper portion 19 of the abrasiveelement, and a cylindrical side wall portion 29 joined to the upperportion and extending downwardly therefrom to a point below the lowersurface 20 of the abrasive element. A pair of slots 30 and 31 are cut orformed in the side wall portion of the housing 25 adjacent the beveledportion 21 of the abrasive wheel, and in alignment therewith. The twoslots are formed in portions of the side wall which lie oppositely ofthe shaft 11. Each slot forms an are which is measured by an angleincluded between radii extending outwardly from the center of the shaftand having a magnitude lying between 30 and degrees. Slot 31 is betterillustrated in Fig. 3 which is a view of the external portion of thesharpener taken at right angles to the section illustrated in Fig. 1. Itwill be understood that only one slot may be formed in housing 25 if sodesired.

Attached to the upper wall portion 28 of the housing 25 is one leg 35 ofan arm member 36. The other leg 37 of the arm member extends upwardlyfrom housing 25 and is spaced from the shaft 11. Engagement means suchas rubber finger 33 is attached to the end of the leg 37 to providemeans for engaging stationary external means such as a portion 39 of thearbor of an electric mixer. It will be understood that when the armmember 38 is in engagement with external means such as electric mixerarbor 39, the housing 25 enclosing the abrasive element will be unableto rotate with the shaft 11 and abrasive wheel 12, since the arm member36 will resist rotation of the housing. Since the housing 25 and slots30 and 31 carried thereby cannot be rotated beyond a certain point whenarm 37 is in engagement with external means, a knife blade may beinserted in one of the slots and guided therein to engage the beveledportion 21 of the abrasive wheel. The blade may then be drawn back andforth within the slot as the abrasive wheel is rotated, causing theblade to be sharpened against the beveled portion of the wheel. Shouldit be desired to sharpen the opposite side of the blade, it may beinserted in the opposite slot to bring the opposite side of the bladeinto contact with the beveled portion of the rotating abrasive wheel,and the sharpening action repeated. It will be particularly noted thatthe provision of the oppositely disposed slots enables both sides of theblade to be sharpened without reversing the position of the knife handlewith respect to the knife blade; in other words, the blade need only beturned over to sharpen one or the other side thereof, as describedabove. It will also be noted that the shaft 11 projects downwardly fromthe mixer arbor 39, with the result that the spin axis of the rotaryabrasive element 12 is suspended vertically. It is by virtue of thisdisposition of elements that the blade to be sharp ened may beconveniently moved horizontally into engagement with the beveled portion21 of the abrasive wheel, on opposite sides of the shaft, so as tosharpen both sides of the blade.

The portion of the shaft 11 projecting upwardly from the housing 25 hasformed thereon attachment means for engagement with retaining meanscarried by an electric appliance such as an electric mixer of the hometype. Such mixers are well known in the art, and for the purposes of thepresent invention, it will be understood that the attachment meansformed on shaft 11 is of such form as will permit the shaft to beattachable to at least one and preferably two or more of the commonbeater retaining devices carried by various mixers of the type referredto. By way of example, the attachment means carried by the shaftillustrated in Fig. 1 includes a pair of slots 43 and 44 formed in theupper end portion 46 of the shaft, the slots being disposed at rightangles and formed inwardly from the end of the shaft to a depth whichapproximates half the diameter of the shaft. In this way, fourprojecting members or lugs 47, 48, 49, and d are formed at the end ofthe shaft. A pair of acuate lugs or ears 51 and 52 are also formed onopposite sides of a portion of the shaft located between the end portion46 of the shaft and the housing 25. in addition, the shaft includes acollar 55' extending along the shaft between the lugs 51 and 52 and thehousing 25. Collar includes an annular groove or recess 56 which carriesa C-shaped wire spring 57 which is adapted to snap into beater retainingmeans carried by an electric mixer.

It is to be noted that the upwardly projecting leg 37 of the arm member36 may be spaced from Shanta a sufficient distance to permit the finger38 to be insertiblc in a bore in an electric mixer arbor adapted toreceive a heater shaft. Thus when the upper end of shaft 11 is insertedin one bore of a mixer, the finger will occupy an adjacent bore so as tobe engaged thereby and to enable the arm 36 to resist rotation of thehousing 25 when shaft 11 is rotated.

Another form of the present invention is illustrated in Fig. 4. Anabrasive wheel or disc 69 is carried by the shaft portion 61 betweenwashers 62 and 63, and a nut 64 is tightened on the threaded lower endportion 65 of the shaft to compress the Washers, the abrasive wheel, andthe housing 66 carried by the wheel between the stepped portion 67 ofthe shaft and the nut. The abrasive wheel has an annular beveled portion68 facing upwardly, and the under surface 69 of the wheel is protectedby the thin housing member 66 which extends outwardly from the shaft 61toward the outer portion of the wheel, and then upwardly to enclose andprotect the side surface 73 thereof. The housing 66 frictionally engagesthe lower surface 69 and side surface 76 of the abrasive wheel to rotatetherewith and protect the wheel during a knife sharpening operation.

A cylindrical bearing 72 such as hearing 26 in Fig. l is fitted over thestepped portion 67 of the shaft so as to be rotatable thereon, and thecylindrical portion 73 of a housing member 74 is pressed over the outersurface of the bearing 72 so as to be rigidly mounted thereon. Thehousing member 74 comprises a plate which extends outwardly from thecylindrical portion 73 and is spaced closely adjacent the annularbeveled portion 68 of the abrasive wheel or disc, so that an annularwedge shaped groove 75 is formed between the outer portion 76 of theplate and the beveled surface 63 of the abrasive wheel. An arm member 78such as the arm member 36 in Fig. 1 is joined to the upper surface ofthe plate 74, and a rubber finger 79 is fitted on the upwardlyprojecting leg 80 of the arm 78.

The upper portion 82 of the shaft carries a rigid cup shaped member 83immediately above the bearing 72. Member 83 comprises a component of theengagement 4 means carried by the upper portion of the shaft, and alsoserves to limit upward travel of the bearing 72 and housing member 74.The engagement means also includes a pair of ears 84 and 85 similar toears 51 and 52 carried by shaft 11 in Fig. l, and an annular recess 86is formed at the extreme upper end portion 37 of the shaft.

When the upper portion 82 of the shaft is inserted in the bore of anelectric mixer which normally carries a beater, the engagement meansdescribed above will connect the shaft in driving or rotating engagementwith the power source, so that the shaft and abrasive wheel may berotated. The upwardly projecting arm will at the same .time serve toprevent rotation of the housing member 74 and thereby prevent dulling ofa knife blade against the under surface $9 of the outer portion 76 ofthe housing member 74, which would otherwise be rotating along with theshaft. The knife blade may be moved into engagement with the beveledsurface 63 of the abrasive Wheel and moved longitudinally in thedirection of the blade to accomplish sharpening thereof. Should it bedesired to sharpen the opposite side of the blade, it need only beturned over and inserted in the groove 75 on the opposite side of theshaft, and the sharpening procedure repeated. 1

The modification of the present invention illustrated in Fig. 5 includesan abrasive wheel 90 carried by shaft portion 91 between washer 92 andcylindrical bearing 93. A nut 94 is tightened on the threaded lower endportion 95 of the shaft to compress the bearing, the abrasive wheel, thehousing member 96 carried by the wheel, and the washer in frictionalengagement between the nut 94 and the shoulder 97 formed on steppedshaft portion 98. The abrasive wheel has an annular beveled portion 100facing downwardly, and the upper surface 101 of the wheel is protectedby the thin housing 96 which extends outwardly from the shaft 91 towardthe side portion 102 of the wheel, and then downwardly to enclose andprotect the side portion. The housing 96 frictionally engages the upperand side surfaces of the wheel to 1'0- tate therewith and protect thewheel during its rotation.

The bearing 93 has a flared portion 105 at its lower end, which servesas a lower limit or stop member for the cylindrical portion 106 ofhousing member 107. Cylindrical portion 106 is freely rotatable aboutthe bearing 93. Housing member 107 comprises a plate which is spacedclosely adjacent the annular beveled portion 100 of the abrasive wheel90 so that an annular wedge shaped groove 108 is formed between theupper surface 109 of the outer portion 110 of the plate and the beveledsurface 100 of the wheel. A circular friction member such as rubber ring111 is joined to the outer extremity of the plate member 107 to serve asa combination braking means and guide for a knife blade when the bladeis inserted in the groove 108. The rotation of the bearing 93 on shaft91 will cause the cylindrical portion 106 of the plate to rotate bymeans of friction, and the plate 107 and ring 111 will necessarilyrotate also. However, when a knife blade is inserted in groove 108, theflat of the blade may be brought into frictional contact with therotating rubber ring 111 to brake its rotation. The blade may then bekept in engagement with both the ring 111 and the upper surface 109 ofthe plate member 107 as the blade is moved longitudinally duringsharpening in the direction of its axis, and the plate 107 will serve asa convenient reaction member or backer therefor. As the blade is movedlongitudinally, the plate and ring will of course slowly rotate sincethey will be in continuous engagement with the moving flat of the blade.Engagement means permitting attachment of the shaft 98 to an electricalappliance such as an electric mixer are also formed on shaft 98, andcomprise elements similar to those illustrated in Fig. 4.

A further modification of the invention is illustrated in Fig. 6. Twothin abrasive discs and 121 are carried in face to face engagement onshaft 122 between supporting plates or housing members 123 and 124. Anut 125.is tightened on the threaded end of shaft 122 to compress theabrasive discs and housing members between the nut and the shoulder 126formed on shaft 122 by collar 127. The housing members 123 and 124rotate with the abrasive discs and serve to protect the flat outersurfaces of the abrasive discs and also to align the discs in planeslying perpendicular to the axis of the shaft 122. The upper disc 120 hasan annular beveled surface 128 facing downwardly toward a similarbeveled surface 129 on the lower disc, facing upwardly. Extendingbetween the two housing members 123 and 124 and between the two beveledsurfaces 128 and 129 is an annular wedge shaped groove 130 within whicha knife blade is adapted to be inserted during a knife sharpeningoperation. When the blade is brought into contact with the rotatingabrasive surfaces 128 and 129 and moved longitudinally, both sides ofthe blade will be sharpened. Should the beveled surfaces on the abrasivediscs wear out, the sharpener components may be readily disassembled sothat the abrasive discs may be replaced. Engagement means permittingattachment of the upper portion 131 of the shaft to an electricalappliance such as an electric mixer are formed on portion 131 of theshaft and comprise elements similar to those illustrated in Fig. 1.These elements comprise a C-shaped spring ring 57 carried by annularrecess 135 in collar 127, and a slot 44 formed in the upper end of theshaft. The upper portion of the shaft is received in core 136 of spindleor socket 137 driven in rotation by electric motor driven worm gear 138meshing with spur gear 139 mounted on the spindle. A driving pin 140extending across bore 136 in the spindle is engaged by the slot 44 whenthe shaft is inserted in bore 136 and serves to connect the shaft to thespindle for rotation. The spindle is itself mounted in casting 141.

The shaft is held in inserted position in bore 136 by expansion of thesnap ring spring 57 into annular recess 142 in spindle bore 136. In thisposition, the snap ring engages both the recess 142 and the annularrecess 135 in the shaft collar 127.

Parts 137 through 141 and 39, are all part of the mixer arbor sectionwhich normally overhangs. a mixing bowl during mixer operation, withheaters attached.

We claim:

1. For combination with a home electric mixer having an arbor sectionadapted to rotate a mixer beater stem, an assembly comprising a rodsized for endwise upward reception in an arbor socket and rotation bythe arbor section with the rod projecting outwardly and downwardly fromsaid socket away from the arbor section, an abrasive disc carried by therod and rotatable coaxially therewith in spaced relation to the arborsection for sharpening a knife blade presented to said disc, meansincluding a cylindrical housing mounted coaxially on the rod to rotatefreely beneath said arbor section and independently of the rod aboutsaid abrasive disc in at least partially protecting relation therewith,said rod projecting upwardly away from the housing, and a handle carriedby the housing extending away from said rod above the bottom level ofthe housing and then projecting upwardly to engage a part of the arborsection spaced from the rod when the rod is rotating for resistingrotation of said housing therewith.

2. The invention as defined in claim 1 in which said housing contains aslot below the level of said handle and through which said knife bladeis insertible for presentation to said abrasive means.

3. The invention as defined in claim 2 including a. sleeve bearing onthe rod spaced inwardly from said handle and mounting said housing torotate freely about the rod in spaced relation to said abrasive disc.

4. The invention as defined in claim 3 including a lug on the rod abovethe housing adapted to interfit with and be rotated by an arbor sectionlug when the rod lug is received into said socket.

5. In combination with a home electric mixer having an arbor sectionadapted to rotate a mixer beater stem, an assembly comprising a rodremovably received endwise into an arbor socket to be rotated by thearbor section with the rod projecting outwardly from said socket awayfrom said arbor section, an abrasive disc carried by the rod androtatable coaxially therewith in spaced relation to the arbor sectionfor sharpening a knife blade presented to said disc, means including acylindrical housing mounted coaxially on the rod to rotate freelybeneath said arbor section and independently .of the rod about saidabrasive disc in at least partially protecting relation therewith, saidrod projecting upwardly away from the housing, and a handle carried bythe housing extending away from said rod above the bottom level of thehousing and then projecting upwardly in engagement with a part of thearbor section spaced from the rod when the rod is rotating for resistingrotation of said housing therewith.

6. The invention as defined in claim 5, in which said housing contains aslot below the level of said handle and through which said knife bladeis insertible for presentation to said abrasive means.

7. The invention as defined in claim 6 in which said handle isrelatively small and projects alongside the arbor section shell.

8. In combination with a home electric mixer having an arbor sectionadapted to rotate a mixer beater stem, an assembly comprising a rodremovably received endwise into an arbor socket to be rotated by thearbor section with the rod projecting outwardly from said socket awayfrom said arbor section, an abrasive disc carried by the rod androtatable coaxially therewith in spaced relation to the arbor sectionfor sharpening a knife blade presented to said disc, a cylindricalhousing at least partially protecting said abrasive means, and meansmounting said housing coaxially and exclusively on the rod to rotaterelative thereto so that the rod may rotate independently of the housingwhile the housing is prevented from rotating relative to said arborsection, said rod. projecting upwardly away from the housing.

References Cited in the file of this patent UNITED STATES PATENTS822,070 McLeran May 29, 1906 1,415,375 Lueben May 9, 1922 2,114,106Geveke Apr. 12, 1938 2,684,561 Lindgren July 27, 1954 2,716,846 GerthSept. 6, 1955 2,722,783 ORussa Nov. 8, 1955 2,735,247 Holzhausen Feb.21, 1956

